As the core equipment for crude oil extraction in oilfields, the pumping unit (nodding donkey) plays a decisive role in crude oil production efficiency and economic benefits through its stable operation. The gearbox, known as the “power heart” of the pumping unit, undertakes the critical functions of power transmission and speed conversion. Gear oil, in turn, serves as the “lifeblood” ensuring the normal operation of the gearbox. It forms an oil film to separate gear meshing surfaces and bearing rolling elements, reducing friction and wear. Through oil circulation, it dissipates heat generated during transmission and maintains a stable internal temperature. Furthermore, it prevents corrosion on gear and bearing surfaces, extends component service life, and directly influences the operational stability and service life of the pumping unit.
Pumping units in oilfields operate under complex and harsh conditions, mostly in open-air field environments, exposed to multiple challenges such as dust, large temperature differences between day and night, and high humidity. They also run continuously under heavy loads, low speeds, and alternating loads. Such operating conditions easily lead to degradation and contamination of gear oil. On the one hand, metal debris from gear meshing and external dust and other impurities mix into the oil, lowering its cleanliness. On the other hand, moisture and air in the environment cause oxidation and emulsification of the gear oil, forming deposits such as sludge and varnish, which reduce the oil’s viscosity and lubricating performance. In addition, oil leakage caused by aged oil seals or defective gearbox housings can result in insufficient oil levels, further accelerating gear wear and creating a vicious cycle: oil degradation → increased wear → elevated temperature → further oil degradation.
For a long time, the oilfield industry has generally relied on regular gear oil replacement to ensure equipment lubrication. Under normal operating conditions, the oil change interval for pumping unit gearboxes is approximately 2,000–3,000 hours or 6–12 months. Under severe conditions such as high temperatures, heavy loads, and high dust levels, the interval is shortened by about 50%. Frequent oil changes not only increase the cost of purchasing new oil but also require substantial labor and material resources. Moreover, equipment shutdowns during oil changes directly reduce crude oil output. Meanwhile, waste gear oil is a refractory petroleum-based pollutant; improper disposal contaminates soil and water bodies, creating environmental pressure. This has become a major pain point hindering oilfield enterprises from reducing costs, improving efficiency, and pursuing green development.
To address these challenges in gear oil application for oilfield pumping units, Qingdao Haina Energy & Environmental Technology Co., Ltd. has launched an on-line purification solution based on its core electro-adsorption purification and regeneration technology, which can significantly extend the service life of gear oil in pumping units and provide an optimized oil management approach for oilfield enterprises. Haina’s electro-adsorption purification technology was listed as a “National Key Encouraged Environmental Protection Technology and Equipment” by the Ministry of Industry and Information Technology and the Ministry of Science and Technology as early as 2017. Its core advantage lies in its purely physical purification method without chemical additives, which preserves the performance of additives in gear oil and enables oil recycling.
Tailored to the purification needs of gear oil in pumping unit gearboxes, Haina’s on-line purification technology operates around the principles of “deep purification and in-situ reuse”. The purification equipment is seamlessly connected to the oil circuit system of the gearbox, realizing on-line circulating purification without shutdown and without affecting normal production. Equipped with a three-in-one composite filter element inside, the equipment adsorbs polar substances in the oil, including oxidation products, colloids, and metal particles, greatly reducing the content of mechanical impurities in the gear oil. This multi-stage synergistic purification mechanism targets the key contaminants causing gear oil degradation, restores the oil’s lubricating, heat-dissipating, and anti-rust properties, and effectively “greatly extends the service life” of degraded gear oil.
In addition to doubling the oil service interval, Haina’s on-line purification technology delivers multiple practical benefits to oilfield enterprises. In terms of cost control, purified gear oil can be reused cyclically, eliminating frequent purchases of new oil. With a waste oil recycling rate of over 90%, it significantly reduces costs for new oil procurement and waste oil disposal. According to application cases of similar industrial equipment, new oil purchase costs can be reduced by more than 70%, and hazardous waste emissions by over 90%. Meanwhile, fewer oil changes reduce equipment downtime, avoid production losses, and improve the operating rate of pumping units. For equipment protection, purified gear oil features higher cleanliness and more stable lubrication performance, reducing wear on core components such as gears and bearings and lowering gearbox failure rates. Statistics show that it can extend the service life of gearboxes by 30%–50% and cut equipment maintenance costs and losses from shutdown repairs. Environmentally, oil recycling reduces the generation of waste gear oil and prevents environmental pollution from oil leakage and waste disposal, aligning with the concepts of green and low-carbon development in oilfield exploitation.
As the oilfield industry evolves toward refinement, energy conservation, and green development, the operation and maintenance of pumping units have become key to enhancing core competitiveness. With its core advantages of “in-situ purification, greatly extended service life, cost reduction, and environmental protection”, Haina’s on-line purification technology breaks the limitations of the traditional oil change model and provides an optimized solution for gear oil management in oilfield pumping units. In the future, with continuous technological iteration and upgrading, Haina will continue to focus on the oil demand of oilfield equipment, improve its on-line purification service system, and provide stronger technical support for oilfield enterprises to reduce operating costs, improve production efficiency, and achieve green development. By maximizing the value of every drop of gear oil, Haina will help promote the high-quality development of the oil extraction industry.
